1. Field
Embodiments of the present invention relate to an organic light emitting display device and a driving method thereof.
2. Description of Related Art
Recently, various flat panel displays that are capable of reducing disadvantages of cathode ray tubes, such as the weight and the volume, have been developed. Typical flat panel displays include liquid crystal displays, field emission displays, plasma display panels, organic light emitting display devices, etc.
Among the flat panel display devices, the organic light emitting display device displays an image using organic light emitting diodes that emit light by recombination of electrons and holes, and has high response speed and is driven at low power consumption.
In general, the organic light emitting display devices are classified into passive matrix organic light emitting display devices (PMOLEDs) or active matrix organic light emitting display devices (AMOLEDs), in accordance with the types or methods of driving the organic light emitting diodes.
The active matrix organic light emitting display device includes a plurality of scanning lines, a plurality of data lines, a plurality of power source lines, and a plurality of pixels coupled to the lines and arranged in a matrix. A pixel commonly includes an organic light emitting diode, a driving transistor for controlling the amount of current supplied to the organic light emitting diode, a switching transistor for transmitting a data signal to the driving transistor, and a storage capacitor for maintaining a voltage of the data signal.
An active matrix organic light emitting display device generally has low power consumption, but may exhibit a non-uniform display because the magnitude of current flowing through an organic light emitting element can vary due to a voltage difference between the gate and the drain of a driving transistor that drives the organic light emitting element—that is, a threshold voltage difference of the driving transistor.
That is, properties of the transistors disposed in pixels vary due to variability in the manufacturing process, and accordingly, the threshold voltages of the driving transistors differ between the pixels. A compensating circuit that can compensate for the threshold voltages of the driving transistors can be additionally formed to remove the non-uniformity between the pixels.
The compensating circuit, however, generally includes a plurality of transistors, capacitors and signal lines for controlling the transistors. Therefore, a pixel including such a compensating circuit may have a reduced aperture ratio and an increased probability of having a manufacturing defect.